I have a 2011 6.7 Cummins fully deleted with mini Maxx tunes, and ever since I deleted and tuned the exhaust brake will not operate, I can get it to work by reloading the tunes but only then it will work only while sitting still, once the truck is driven it doesn’t work anymore, then have to reinstall, I tried uninstalling and going back to stock and it does the same thing. I even changed the turbo assembly and no change either. Any thoughts or ideas would be helpful and appreciated

 

did you ever figure this out? I have same problem